Rotary pump or the like



June 9, 1942. H. G. laowERlNcs ROTARY PUMP OR THE LIKE Filed Dec. 18, 1940 Snventor Gttornegswam Patented June 9, 1942 2.286.031 v no'rlmr PUMP onl THE um;

Henry G. Bowering, Needham, Mass., assigner to Kinney Manufacturing Company, Jamaica Plain, Mass., a corporation o! Massachusetts 4Original application January 22, 1938, Serial No.

186,402. vDivided and this application December 18, 1940, -Serial No. 370,694

(Cl. S-126) 14 Claims.

My present invention relates to improvements in rotary pumps and the like, and this application is a division of my co-pending application, Serial No. 186,402, illed January 22, 1938.

In the manufacture of pumps, particularly those having rotors of the gear type, several factors are involved that limit their capacity and their utility. The attendant problems are present in the manufacture of such rotors wherein the accurate cutting of the teeth is both expensive and diiilcult in the general construction of pumps wherein the load of the projected area of the rotors improves definite limitations, and in the operation of the assembled pumps wherein the' pressure of pocketed fluids introduces severe'limi tations.

In accordance with my invention, the solution ofthe problems depends in part on the reduction ofthe load of the projected area of the rotors, in part on the `by-passi'ng of entrapped fluids to the outlet side of the pump, and in part on the construction df` the teeth of the rotors to reduce their lpositive meshing portions to a minimum.

With pumps in accordance with my invention, regardless of whether the gear teeth are of the spur gear type or of the herringbone type, or whether rotors of other types are employed, increased economy and efllciency in both construction and operation are effected in pumps embodying one or more of these features.

In the accompanying drawing, I have shown an embodiment of my invention from which its several novel features and advantages will be readily apparent.

In the drawing:

Fig. ,1 is a vertical section through a pump in accordance with my invention.

Fig. 2 is a section along the lines 2-2 of Fig. 1.

Fig. 3 is a view showing the relation of the gear l teeth to the relief passages through the rings.

Fig. 4 shows in perspective one of the rotors.

Fig. 5 is a fragmentary end view of intermeshing teeth in accordance with my invention, and

Fig. 6` is a fragmentary view showing a modification of my invention. Y

I haveindvicated at I a pump casing having end wens 2. The ena walls z have flanges s andere provided` with apertures to receive the rings l extending within the casing and including offset portions Ii fitting within the flanges 3 against the end walls 2.

Bearings 6 are mounted between the portions l yof the rings 4 and the shafts 1 and 8 for the I0 are annularly undercut as at II to receive the rings I with ends of the rotor teeth I 2 overhanging the rings l. By this construction, the load of the 'projected area of the rotors on the bearingsl on each rotor shaft. Where a rotor is counter- 1 bored to establish a recess having its maximum diameters equal to the root diameter of the teeth and its minimum diameters preferably greater than the diameter of the rotor shafts, the pro- 4 iected area is reduced by an` amount equal to the root diameter multiplied by the depth of the recess, or recesses, if the rotor-is counterbored at each end.

In the embodiment of my invention shown in the drawing, the rotor I is-the driving rotor and the rotor III is driven thereby. The vteeth I2 are l shown as of the herringbone type. End plates I3 are attached to the flanges 3 to hold the rings I and the bearings 8 in position and to enclose the ends of the shaft 8 and one end of the shaft 1. As the shaft 'I is the drive shaft, one of the end plates I3 is apertured and includes a packing rotors' and III respectively. The rotors 0 and 55 box Il for the protruding end of the shaft 1.

It will be understood that working clearances are provided between the rotors and their'teeth and the casing and the side walls and that like working clearances are provided between the rings and the surfaces of the rotors presented by the end recesses. The extent to which the rotors are counterbored is limited by the requirement of ensuring adequate strength to the unsupported parts of the teeth under maximum loads.

While the rotor teeth I2 may be of any de-v sired type, I have shown in the drawing a gear tooth construction of particular importance. As

-' shown most clearly in Figs. 3-5, the gear teeth I2 of each rotor are formed as at I2n with driving portions to mesh with like portions of the other rotor so that the rotor I0 is positively driven by the driving rotor 9. Laterally of the portion I 2l, each tooth of each rotor is formed with portions I2bv relieved sumciently to enter without contact between like portions of a pair of teeth of the other rotor asl shown in Figs. 2 and 5 to cooperate with the first-named portions only in pumping fluids. The relation of the portions i2 to the portions i2 is determined by l the maximum load under which a particular pump is to be operated and the extent to which the tooth portions I2b are relieved is also variable. The rotors may be undercut so thatV the portions I2b entirely overhang the rings d. i

By this construction, theexpense of the rotors is substantially reduced since the teeth are formed to intermeshv accurately only in the driving zone defined by the teeth portions i2i. At the same time, the capacity of the pump is in,- creased and the problems presented by fluid pressure developed as fluids are entrapped as teeth in mesh are minimized. While I have shown only gear teeth of a herringbone type, it will be obvious that other types of gear teeth may be similarly constructed.

With pumps, the rotors of which have intermeshing gear teeth, the pressure developed by fluids entrapped as the teeth intermesh has been a recognized problem hitherto only partially solved by drilling through the teeth to provide relief conduits.

In accordance with my present invention, the fixed rings I aiford a simple solution to the problem. I accomplish this result by providing relief ,conduits to transfer entrapped fluids to the discharge or outlet of the pump. I preferably accomplish this result, as may be most clearly shown in Fig. 5, by providing the-rings 4 with grooves I5 and IS adjacent the zone wherein the teeth intermesh and the outlet side of the pump respectively. The rings are bored as at il and the passages il are connected to the grooves i5 by bores i8. The use of the grooves i4 and i5 is desirable, particularly with angularly disposed teeth, as otherwise the relief conduits would be intermittently blocked by the portions .of the teeth overhanging the rings d.

As in certain instances, it may be desirable to utilize to some extent the pressure of the entrapped fluid, I have shown in Fig. 6 a passage I9 through the ring t in communication with the passage i1 and a bore t through the oiset portion 5 and a flange 3. A conduit 2i controlled by a valve 22 transfers fluid to the outlet. By adjusting the valve 22, the pressure of the entrapped fluid may be varied in relation to the viscosity of the fluid.

It will be appreciated that certain features of my invention may be utilized with any type of rotor. For example, the undercutting of the teeth including a portion formed to mesh in driving contact with like portions of the teeth on the other rotor so that said other rotor is positively rotated by the driving rotor, and a portion to enter without driving contact between like portions of a pair of teeth of the other rotor to cooperate with said second-named like portions only in the transfer of iluid from said inlet to said outlet.

2. A pump comprising a casing `having an intake and an exhaust, and a pair of unitary rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality of teeth equally spaced around the periphery of said rotors and extending from end to end thereof, each of said teeth including an intermediate portion formed to mesh in driving contact with like portions of the teeth on the other rotor so that said other rotor is positively rotated by the driving rotor, and end portions to enter freely without driving contact between like portions of a pair of teeth of the other rotor to cooperate with said second-named like portions only in the transfer of fluid from said intake to said exhaust.

3. The pump of claim 2 in which the teeth are of a herringbone type.

4. A pump comprising a casing having an inlet and an outlet, and a pair of rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality or teeth, each of said teeth including a driving mrtion formed to mesh in driving contact with like portions of the teeth on theother rotor so that said other rotor is positively rotated by the driving rotor, and end portions to enter freely without driving contact between like portions of a-pair of teeth or the other rotor to cooperate with said second-named like portions only in the transfer of fluid from said inlet to said outlet, said rotors having annular recesses in their ends exposing the end portions of said teeth, and rings carried by said casing entrant of said recesses.

5. A pump comprising -a casing having an inlst and an outlet, and a pair of rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality of teeth, each of said teeth rotors at their root diameters and the use of the rings d is of advantage in anyl rotary pump as it makes possible a very substantial reduction of the load on the bearings of the projected area of the rotors and accordingly much closer clearances are possible.

It will also be obvious that with rotors of the gear type, the driving part characterized by the gear portions I2 may be located medially of the rotors as shown or adjacent one end. Where one rotor is driven by the other, they are under,- cut only under the elieved parts of the teeth, although this is not a requirement where timing gears are employed. y

What I therefore claim and desire to secure by Letters Patent is:

4l. A pump comprising a casing having an inlet and an outlet, and a pair of unitary rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality of teeth equally spaced around the periphery of said rotors and extending from end to end thereof, each of said including a driving portion formed to mesh in driving contact with like portions of the teeth on the other rotor so that said other rotor is positively rotated by the driving rotor, and an end portion to enter freely Without driving contact between like portions of a pair of teeth of the other rotor to cooperate with said secondnamed like portions only in the transfer of fluid from said inlet to said-outlet, said rotors each being recessed to expose at least a part of said end portions of said teeth, and rings carried by said casing entrant of said recesses.

6. A pump comprising a casing having an inlet and an outlet, and a pair of rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality of teeth, each of said teeth including a driving portion formed to mesh in driving contact with like portions of the teeth.

on the other rotor so that said other rotor is positively rotated by the driving rotor, and portions to enter freely without driving contact between like portions of a pair of teeth of the other rotor to cooperate with said second-named like portions only in the transfer of fluid from said inlet to said outlet, said rotors having annular recesses in their ends exposing the ends of said teeth, rings carried by said casing, entrant of said recesses, and said rings being each formed with an aperture to vent to the exhaust side of saidpumpuids entrapped by intermeshing teeth of said rotors.

7. A pump comprising a casing having aninlct and an outlet, and a pair of rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality of teeth, each of said teeth including a driving portion formed to mesh in driving contact with like portions of the teeth on the otherv rotor so that said other rotor is positively rotated by the driving rotor, and an end portion to enter freely between like portions of a pair of teeth of the other rotor to cooperate with said second-named likeportions only in the transfer of fluid from said inlet to said outlet, said rotors having annular recesses in their ends exposing the ends of saidisecond-named tooth portions, rings carried by said casing entrant of said recesses, and means to vent fluids entrapped by intermeshing teeth of said rotors, said means including a passage in one of said rings.

8. A pump comprising a casing having an inlet and an outlet, and a pair of rotors rotatably supported within said casing, one of said rotors constituting the driving rotor, each of said rotors including a plurality of teeth, each of said teeth including a driving portion formed to mesh 11. A pump comprising a casing having an inlet, an outlet and end walls, a pair of shafts, bearings in support of said shafts, a rotor carried byeach of said shafts within said casing, said rotors including intermeshing teeth to cooperate in pumping fluid from said inlet to said outlet as said rotors are rotated, said rotors and said teeth having working clearances between said walls and said casing respectively to rotate without contact therewith, each of the ends of said rotors being counterbored to establish an' annular recess with its maximum diameter equal to the root diameter of the teeth and its minimum diameter not less than the diameter of said shafts, and annular rings rigidly supported by said end walls, said rings having an outside diameter slightly less than the root diameter of said' teeth and an inside diameter slightly greater than the minimum diameter of said recess to provide working clearances and to reduce the projected areas of saidrotors and the corresponding load on said shafts and bearings and to permit minimum working clearances between said rotor and said teeth and said end in driving contact with like portions of the-teeth on the other rotor so that said other rotor is positively rotated by the driving rotor, and an end portion to enter freely between like portions ofl a pair of teeth of the other rotor to cooperate with said second-named like portions only in the transfer of fluid from said inlet to said outlet, saidf rotors'having annular recesses in their ends exposing the ends of said second-named tooth portions, rings carried by said casing entrant of said recesses, means to vent fluids entrapped by intermeshing teeth of said rotors, and said means including a conduit extending through one of said rings and saidI casing to Ebe connected to the outlet side of said pump, anda valve in control of said conduit. .V y

9. The pump of claim 7 in which the means to vent entrapped fluids includes a groove in each ring in the zon..l wherein the teeth intermesh, a like groove in the ring adjacent the outlet side of said pump, and a passage interconnecting each of said grooves, said grooves being of sufilcient I 4length and being disposed relative tothe teeth of the rotors so that said passage is not blocked intermittently by said teeth.

A10. A pump comprising a casing having an inlet and an outlet, and a pair of rotors having a plurality of intermeshing blades rotatably supported in said casing, each of said rotors having an annular recess in at least one of its ends exposing the end portions of said blades, rings carried by said casing entrant of said recesses, and each of said rings being formed with a lgroove in the none wherein the teeth intermesh. a like groove in the ring adjacent the outlet side of saidv pump and a passage interconnecting each of said grooves, said grooves being disposed relative to the teeth of the rotor so that said passage is not intermittently blocked by said teeth.

walls and said casing respectively.

12. The pump of claim 11 in which the rings include a flanged hub portion, and the bearings are mounted between said hub portion and said shaft, and means carried by said end walls maintaining saidring and said bearings in position.

13. A pump comprising a casing having an inlet, an outlet, and end walls, a pair of shafts, bearings in support of said shafts, a rotor carried by each of said shafts within said casing, said rotors including intermeshing teeth to cooperate in pumping fluid from said inlet to said outlet as said rotors are rotated, said rotors and said teeth having working clearances between said walls and said casing to rotate without contact therewith, one end of each rotor being formed to establish an annular recess with its maximum diameter at least equal to the root diameter of the teeth and its minimum diameter not less than the diameter of said shafts, and annular rings rigidly-supported by said end walls, said rings having an outside diameter slightly less than the root diameter of said teeth and an inside diameter slightly greater than the minimum diameter of said recesses to provide working clearances, whereby the projected area of said rotors and the corresponding load on said' shafts' and bearings is reduced and minimum working clearances between said rotor, said teeth and said end walls and saidcasing may be established and maintained.

14. A pump comprising a casing having an inlet and an outlet. anda pair of rotors rotatably supported Iwithin said casing, said rotors including intermeshing teeth to cooperate in pumping fluid from the inlet to the outlet as said rotors are rotated, each loi! said rotors having an annular recess in at least one of its ends exposing the end root portions of said teeth, rings carried by said casing entrant of said recesses, and means to vent fluids entrapped as said teeth intermesh, said means including a conduit extending through one of said rings and said casing, and a valve in control of said conduit.

HENRY c+. nomma. 

